The present disclosure generally relates to antennas that convert RF power to DC power, and specifically to designs of such antennas used in high-voltage applications.
A rectenna is a special antenna that captures and converts RF or microwave power to DC power. The rectenna may be used as the receiving terminal of a power transmission system. In this configuration, the terminal may deliver DC power to a load where physical transmission lines are not feasible. The power delivery may be through free space. The rectenna may also be useful in applications where DC power needs to be distributed to a large number of load elements that are distributed spatially. The power distribution is achieved by the dispersive nature of microwave energy in space. The dispersion may substantially reduce the need for physical interconnects to individual load elements. The rectenna may use the dispersive nature of the microwave power to combine the power from many elements, which are spatially separated by the element spacing of the array or panel. Therefore, the effective area of the entire rectenna panel determines the total power received by the panel.
An application for rectennas may involve the transmission of power to actuators. For example, the actuators may control the position of individual surfaces of a spacecraft-mounted optical reflector. The use of rectennas may simplify the design of the multi-surface reflector by eliminating the need for a wiring harness to distribute power to the individual actuators. Further, the rectennas may also have associated circuitry to provide control signals to each actuator by proper modulation of the incident microwave beam. However, the actuators often require high voltage for operation. For example, the high voltage may be on the order of about 50 volts.
The present disclosure defines an energy transfer system that includes patch elements, shielding layers, and energy rectifying circuits. The patch elements are arranged to face a source of radio frequency energy. Each of the patch elements has a first surface facing the source of energy, and a second surface opposite the first surface and facing away from the source of energy.
Each shielding layer is located facing the second surface, such that each of the patch elements is coupled between the source of energy and the shielding layer. The shielding layer includes at least one opening that allows radio frequency energy to pass through to a second side thereof. The openings are formed and positioned to receive the radio frequency energy and to minimize any re-radiating back toward the source of energy.
The energy rectifying circuit includes a circuit for rectifying the radio frequency energy into dc energy. At least a part of the energy rectifying circuit is on the second side of the shielding layer. The circuit is separated from the source of energy by the shielding layer. The energy rectifying circuits are arranged in an array to provide a sum of dc energy generated by the energy rectifying circuit.
The present disclosure also defines a method of receiving and transducing energy. The method includes separating a first part of the energy having a first characteristic, from a second part of the energy having a second characteristic, coupling the first part of the energy to a first circuit portion of an energy receiving board, and coupling the second part of the energy to a second circuit portion of the energy receiving board. The second circuit portion is spaced apart from the first circuit portion. The method further includes appropriately coupling energy receiving boards to add energy received by each energy receiving board.